25. Classify the following as element, compound or mixture and explain how do you know? a) NaCI + H2O
b) C2H4O
c) O2
d) Co
e) CO
f) H2 + O2
g) H2O2

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.